Once in a while, an everyday item strays so far from its original functional purpose that one finds oneself wondering whether civilisation really has plumbed so far into the depths of decadence that only universal and lasting doom is left.

If that sounds a little melodramatic, not to mention alliterative, I’m afraid coloured sunglasses are to blame. By coloured, I don’t mean the various muted shades of tortoiseshell or black that used to pass for choice in the dim and distant past when Reason still held sway. And by sunglasses, I don’t mean the lenses, where colour may indeed serve a useful ophthalmic purpose. I mean the frames. For as you will have noticed – unless you have been fortunate enough to have spent what passes for our laughable summer on Pluto – red, yellow, green and, lawksamercy, pink sunglasses are the very height of fashion this year.

That’s progress for you: last year, we had the very silly-looking white sunglasses craze. This year, we have the completely stupid school of Bob the Builder, multicoloured, very plastic look. Which means that if spending half the morning co-ordinating your hair extensions with your vast collection of Birkins isn’t enough to fulfil you creatively as an artist, then you can at least bolt on another hour or two while you decide whether to match or clash your specs with your toenails.

Perhaps it’s the experimental nature of this display that in part explains the appeal of coloured sunnies. Or perhaps Ray-Ban just sent out loads of freebies. Either way, all the usual suspects have been turning out in support of this trend: Lily Allen in a lime pair, Paris in – surprise, surprise – a pink pair, Jessica Simpson in a red pair, Drew Barrymore and Sienna in white (must be a retro thing), and where they so fearlessly tread, others follow. Type “coloured sunglasses” into Google and the screen leaps to life with blogs from lesser mortals plaintively asking where they can get hold of cheaper versions (Topshop, for starters).

The funny thing is that while sunglasses are supposed to be the modern-day equivalent of a mask, the expression on all these coloured sunglasses wearers is all too blatantly apparent. It’s the “Hey, I don’t take myself seriously, you know; now where’s that assistant who wipes the gunk off my shoes?” look. If sticking your tongue out at paps wasn’t so 2007 and flicking a V for Victory wasn’t so 1945, they’d do that instead. So top marks for ingenuity. And A* all round, I suppose, for reacting to this rubbish summer with an utterly rubbish pair of sunglasses.

As for why mere mortals are buying them in packs, my extensive research suggests that they find the classic tasteful sunglasses of their mothers boring. That would be boring in the same way that Mies van der Rohe is boring. Oh well, they’ll learn.

Times recommends

• Babyboomers still partying on in their sixties
• Do I have a chance of finding love again?
• Video: How to do party make-up